These COMP Cams Hi-Tech pushrod length checking tools are precision crafted from steel alloy and black oxide for years of accurate measurements. Their unique designs are easy to read and eliminate the need for expensive calipers. Each complete revolution is equal to .050 inch. Having the correct length pushrods in your engine is a critical factor in proper rocker arm geometry and these are the best tools to measure pushrod length. Minimum length, 6.800″, maximum length, 7.800″. Read about how to measure pushrod length HERE.